Gas sensors of this type have been known in many different forms and have been used for various applications, in chemical production plants, laboratories and plants in which gases are used as operating materials, for monitoring, control or as an alarm.
One problem that arises in connection with such electrochemical gas sensors is that changes in the humidity of the ambient atmosphere may lead to changes in the value of the measured signal and especially to a variation in the zero signal of the gas sensor, in the signal value that is furnished by the gas sensor when the concentration of the gas being measured in the ambient atmosphere is zero. If there are variations in the zero signal in the case of changes in the ambient humidity, an excessively high or excessively low measured gas concentration may be erroneously mimicked, which may lead to the triggering of false alarms or to the suppression of states of alarm when an alarm should have actually been triggered. The problems being described here, which are caused by the measured signal being affected by changes in the humidity of the ambient air, are especially pronounced in the case of rapid changes in humidity and they subside thereafter over time.
Prior-art filters are not particularly suitable for handling these problems, because they are consumed rapidly because of seasonal and weather-related variations in humidity and therefore they would have to be replaced frequently.